Preheat the oven to 375 degrees. Spray baking dish with non-stick spray.
Pour the French Onion soup (undiluted) into the bottom of the baking dish.
Lay the chicken on top of the soup.
Slather the chicken with mayonnaise. Sprinkle with dry French onion soup mix, add the bread crumbs on top and finish with a slice of cheese on top of each piece of chicken.
Bake for 20–25 minutes, or until the chicken reaches 160°F. Remove from the oven, tent loosely with foil, and let rest for 5 minutes until it reaches 165°F.
Notes
Storage - Let the chicken cool completely, then store leftovers in an airtight container in the refrigerator for up to 3 days. This dish also freezes well—place in a freezer-safe container for up to 2 months, making sure to include plenty of sauce to keep the chicken from drying out.When ready to reheat, thaw overnight in the refrigerator and warm in a 350°F oven, covered, for about 20 minutes or until heated through.